The one thing they hate more than anything else is ab-initio (i.e. zero hours) student pilots turning up who've spent time on the computer flight sim. It always ends up with "the talk" where the instructor politely invites the student to put a stop to their sim career whilst they get some real hours under their belt.
Basic flight training is done VFR, i.e. "seat of your pants", based on visual environmental cues, combined with radio where required. The student learns to juggle the fundamental Aviate, Navigate, Communicate routine ... and its always evident who has come from a flightsim background, because they whilst they might be OK at some parts of Aviate they are scary at Navigate, shit at Communicate and just a complete liability when it comes to combining all three.
People coming from a flight-sim background have too many bad habits ingrained which need to be bashed out of them. Its a waste of everyone's time, and its a waste of the student's money because they are throwing money down the pan which could have been avoided if they spent less time sim.
Now, later on in your flying career. Once you get into instrument flight, then CAREFUL use of a flight sim can be useful. But in the end, there's still no substitute for real-life.